The present study was aimed at verifying the occurrence, if any, of in vivo oxidative DNA damage in FA homozygotes, their parents and siblings. 8-Hydroxy-2'-deoxyguanosine (8-OHdG) was measured, by HPLC/EC, in DNA from circulating blood leucocytes from FA homozygotes and their relatives and compared with a group of paediatric and adult healthy subjects. The population studied consisted of: (i) 15 FA homozygotes; (ii) 24 FA heterozygotes; (iii) 11 siblings. The 8-OHdG level in FA homozygotes was significantly higher with respect to age-matched controls, with a mean level of 33.3 +/- 6.8 (mean +/- SE) and 3.9 +/- 0.26 8-OHdG/10(5) dG respectively. The FA parents (heterozygotes) also displayed higher 8-OHdG levels relative to controls. The release of hydroxyl (.OH) and .OH-like radicals from leucocytes was determined by luminol-dependent chemiluminescence (LDCL) in a subgroup of FA homo- and heterozygotes, showing a very large in vivo formation of non-superoxide radicals. Chromosomal instability was also measured in the FA population. When relating either 8-OHdG or LDCL levels to spontaneous or diepoxybutane-induced chromosomal instability (S-CI and DEB-CI respectively), a significant correlation was observed between the 8-OHdG, LDCL and S-CI data. Within families a positive association was found between 8-OHdG levels in homozygotes and their related heterozygotes, suggesting segregation of the genetic defect(s) underlying the abnormal oxidative metabolism. The present study provides evidence for an in vivo pro-oxidant state in FA, in terms of excess formation of .OH and .OH-like radicals, and of DNA hydroxyl adducts. This finding appears to be shared by homozygotes and, to a lesser extent, by heterozygotes.

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The aim is to determine the monocyte count performance of the Bayer Diagnostics ADVIA120 and Coulter LH 750 automated haematology analysers and the results obtained by these two instruments were compared with those provided by Becton Dickinson FACScan flow cytometer using the combination of CD45/CD14 MoAb. Linearity and imprecision were also evaluated. The linearity of both instruments was good. Coulter LH 750 showed better precision (4.3%) than ADVIA 120 (9.0%) both within and between batch. A significant correlation (r = 0.973) was found between the LH 750 and the flow cytometry method, while a modest one was observed between the latter and the ADVIA 120 (r = 0.880). When comparing the percentage of monocytes by means of one-way anova and Tukey test, it was found that the LH 750 provided the closest results in comparison with flow cytometry, with no statistical difference between the means (mean difference MO% = 0.6); however the difference was statistically different between the ADVIA 120 and flow cytometry (mean difference MO% = -4.06). These data were confirmed by Altman-Bland and Deming regression analyses.